<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
<script>


//1
//	var a;
//	alert(a)


//2
//var string1="i like 'javascript'";
//var string2='i like "javascript"';
//var string3="i like \"javascript\"";
//var string4='i like \'javascript\'';
//document.write(string1+"<br />")
//document.write(string2+"<br />")
//document.write(string3+"<br />")
//document.write(string4+"<br />")	



//3
//
//document.writeln("<pre>")
//document.writeln("javaScript\n轻松自学 javascript!")
//document.writeln("</pre>")


//4
var myString=new String("aBcDeFg");
var lower=myString.toLowerCase();
alert(myString+"转换为小写字母后为："+lower)
	
</script>
		
	</body>
</html>
